What could be causing the pain in my left breast? 12 years post-op.

Thank you for sharing your question.  This is a question best addressed through an in-person examination of your left breast tissue and implant.  Most likely you are experiencing some mild hardening of the surrounding implant capsule, termed a contracture.  Without photographs however it is difficult to render definite advice.  Follow up with your surgeon, they are in the best position to help advise you.  Best wishes.

I would encourage you to seek an in person consultation and exam with your plastic surgeon or other board certified plastic surgeon. There are a number of things that could be causing your discomfort. The most common issue is capsular contracture or hardening of the scar tissue surrounding the implant. This would not be an emergent issue but really the best way to determine what is going on is an in person physical exam. They may choose to order some breast imaging at that time. I hope that helps.